[PATCH v6 15/17] cxl/pci: Add support to assign and clear pci_driver::cxl_err_handlers

[Terry Bowman]

pci_driver::cxl_err_handlers are not currently assigned handler callbacks.
The handlers can't be set in the pci_driver static definition because the
CXL PCIe Port devices are bound to the portdrv driver which is not CXL
driver aware.

Add cxl_assign_port_error_handlers() in the cxl_core module. This
function will assign the default handlers for a CXL PCIe Port device.

When the CXL Port (cxl_port or cxl_dport) is destroyed the device's
pci_driver::cxl_err_handlers must be set to NULL indicating they should no
longer be used.

Create cxl_clear_port_error_handlers() and register it to be called
when the CXL Port device (cxl_port or cxl_dport) is destroyed.

Signed-off-by: Terry Bowman <terry.bowman@xxxxxxx>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Reviewed-by: Ira Weiny <ira.weiny@xxxxxxxxx>
Reviewed-by: Gregory Price <gourry@xxxxxxxxxx>
---
 drivers/cxl/core/pci.c | 59 ++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 57 insertions(+), 2 deletions(-)

diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
index f154dcf6dfda..03ae21a944e0 100644
--- a/drivers/cxl/core/pci.c
+++ b/drivers/cxl/core/pci.c
@@ -860,8 +860,39 @@ static pci_ers_result_t cxl_port_error_detected(struct pci_dev *pdev)
 	return __cxl_handle_ras(dev, &pdev->dev, ras_base);
 }
 
+static const struct cxl_error_handlers cxl_port_error_handlers = {
+	.error_detected	= cxl_port_error_detected,
+	.cor_error_detected = cxl_port_cor_error_detected,
+};
+
+static void cxl_assign_port_error_handlers(struct pci_dev *pdev)
+{
+	struct pci_driver *pdrv;
+
+	if (!pdev || !pdev->driver || !get_device(&pdev->dev))
+		return;
+
+	pdrv = pdev->driver;
+	pdrv->cxl_err_handler = &cxl_port_error_handlers;
+	put_device(&pdev->dev);
+}
+
+static void cxl_clear_port_error_handlers(void *data)
+{
+	struct pci_dev *pdev = data;
+	struct pci_driver *pdrv;
+
+	if (!pdev || !pdev->driver || !get_device(&pdev->dev))
+		return;
+
+	pdrv = pdev->driver;
+	pdrv->cxl_err_handler = NULL;
+	put_device(&pdev->dev);
+}
+
 void cxl_uport_init_ras_reporting(struct cxl_port *port)
 {
+	struct pci_dev *pdev = to_pci_dev(port->uport_dev);
 
 	/* uport may have more than 1 downstream EP. Check if already mapped. */
 	mutex_lock(&ras_init_mutex);
@@ -872,9 +903,15 @@ void cxl_uport_init_ras_reporting(struct cxl_port *port)
 
 	port->reg_map.host = &port->dev;
 	if (cxl_map_component_regs(&port->reg_map, &port->uport_regs,
-				   BIT(CXL_CM_CAP_CAP_ID_RAS)))
+				   BIT(CXL_CM_CAP_CAP_ID_RAS))) {
 		dev_err(&port->dev, "Failed to map RAS capability\n");
+		mutex_unlock(&ras_init_mutex);
+		return;
+	}
 	mutex_unlock(&ras_init_mutex);
+
+	cxl_assign_port_error_handlers(pdev);
+	devm_add_action_or_reset(&port->dev, cxl_clear_port_error_handlers, pdev);
 }
 EXPORT_SYMBOL_NS_GPL(cxl_uport_init_ras_reporting, "CXL");
 
@@ -886,6 +923,8 @@ void cxl_dport_init_ras_reporting(struct cxl_dport *dport)
 {
 	struct device *dport_dev = dport->dport_dev;
 	struct pci_host_bridge *host_bridge = to_pci_host_bridge(dport_dev);
+	struct pci_dev *pdev = to_pci_dev(dport_dev);
+	struct cxl_port *port;
 
 	dport->reg_map.host = dport_dev;
 	if (dport->rch && host_bridge->native_aer) {
@@ -901,9 +940,25 @@ void cxl_dport_init_ras_reporting(struct cxl_dport *dport)
 	}
 
 	if (cxl_map_component_regs(&dport->reg_map, &dport->regs.component,
-				   BIT(CXL_CM_CAP_CAP_ID_RAS)))
+				   BIT(CXL_CM_CAP_CAP_ID_RAS))) {
 		dev_err(dport_dev, "Failed to map RAS capability\n");
+		mutex_unlock(&ras_init_mutex);
+		return;
+	}
 	mutex_unlock(&ras_init_mutex);
+
+	if (dport->rch)
+		return;
+
+	port = find_cxl_port(dport_dev, NULL);
+	if (!port) {
+		dev_err(dport_dev, "Failed to find upstream port\n");
+		return;
+	}
+
+	cxl_assign_port_error_handlers(pdev);
+	devm_add_action_or_reset(&port->dev, cxl_clear_port_error_handlers, pdev);
+	put_device(&port->dev);
 }
 EXPORT_SYMBOL_NS_GPL(cxl_dport_init_ras_reporting, "CXL");
 
-- 
2.34.1